hi there, rhythm method is one of the most oldest means to chart your fertility and this is often used for those couples who are in family planning which they are not able to use some alternative methods like the Catholics.

the menstrual cycle is categorized into some several phases and as to cycle length differs from women, each of menstrual phase durations also varies. the first phase is know to be as the menstrual phase and this is the first day of each cycle classified to as the first day of your menstruation. this will lasts for about 3 and 5 days and it is a period of relative infertility as its classifications.

well, if you want rhythm method to be effective, you should conjunct it with more of those indicative predictors like charting BBT and your cervical mucus on to a monthly basis to be able to give you a better picture of when is your fertility peak tumbles and enable for you to work on the best of the time to try and to conceive.